Nothing about the following discussion is to be interpreted as an admission of prior art.
A cajon is well known as prior art. A cajon is a musical instrument that originated in South America. The original cajons were made out of discarded shipping crates by slaves. Subsequently, they come in all shapes and sizes.
The most common form of the cajon is a wooden box built to various sizes that is played with the performer sitting on it. The front panel or face of a cajon is most commonly wood ply, roughly ⅛″ to ¼″ in thickness, where the outer surface area is struck by the hand of the cajon player to achieve an audible effect. The front panel is normally mounted to the body using screws, except for the upper corners. Generally, the upper corners of the box are sanded down & tapered back creating a small gap between the front panel and the cajon body. This allows for the player to strike either upper corner causing the front panel to slap against the body causing a considerably higher pitched tonal response than any other area of the cajon. Generally, there is a hole or multiple holes, of various sizes on the cajon body itself to allow for relief of air flow resulting from the cajon being struck by the player, and to serve to amplify the sound coming from within the cajon. Any shape, such as a square cut out or portal opening can be used to achieve a similar effect.
With the cajon being an integral instrument in Flaminco and more recently in various other musical styles, the need for a better sounding cajon becomes more aparent, thus, sound quality becomes a central issue. Attempts to improve sound quality have been made in the prior art. U.S. Ser. No. 7,485,790 discloses a cajon with wires attached to the inside wherein each wire acts as a damping element. U.S. Ser. No. 7,482,522 further adds a pedal and snare carpet to change the tone of the instrument.
The prior art cajons require wires, guitar strings, or a snare carpet to be mounted up against the inside front panel. This creates certain problems. In the case where guitar string(s) are used, tuning or tension adjusting becomes an issue, thus the mounting of them becomes awkward and complicated. Multiple strings not being in tune with each other produce undesirable tones. Where a snare carpet is used, overall sound quality and complexity in design are an issue. Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.